1. Field of the Invention
This invention relates to a process for determining the alignment of a cylindrical body, especially a shaft or roller, with respect to a reference direction which is dictated especially by another roller or shaft.
2. Description of Related Art
Published German Patent Application DE 195 46 405 A1 (corresponding to Published International Application WO/9721980 and U.S. patent application Ser. No. 09/077,887) discloses a process for parallel alignment of shafts or rollers, a position measurement probe being used which comprises at least one optical gyro and which is provided with a contact surface for defined attachment to the body to be aligned which has two planar flat sections which include a flat angle relative to one another. Furthermore, the position measurement probe is provided with a double acting inclinometer for fixing the angular position of the position measurement probe with reference to the vertical. In the determination of the alignment of two bodies relative to one another, the process lies in that, first of all, by attaching the position measurement probe to the first body in a stipulated first measurement plane, a reference position is determined, and then, within a stipulated time interval after determination of the reference position, the location of the second body in a plane which agrees with the first measurement plane or which is parallel to it is determined by means of attachment of the position measurement probe to the second body. If necessary, other position measurements of this type, i.e., a reference position determination on the first body with subsequent position measurement on a second body, can be taken in a second measurement plane which includes a defined angle, for example, 90xc2x0, with the first measurement plane. The respective measurements are taken by the position measurement probe, if the bodies to be aligned are shafts or rollers, being manually attached to the peripheral surface of the shafts or rollers.
Japanese Laid-open patent application S60-158310 discloses an angle measurement method and device for measuring the angle between two planes that form two mutually separate structures in constructions sites, shipbuilding yards and the like. In the disclosed method and device, angular velocities are sensed by mechanical gyros, and resultant angular velocity signals are integrated to convert them into angles. However, mechanical gyros do not produce a high degree of precision, and there is no disclosure as to if or how the method and device might be applied to cylinders or rolls.
In cylindrical bodies with a large diameter, as a result of the practical limitation of the dimensions of the position measurement probe to be attached and the resulting limited size of the attachment or contact surface of the position measurement probe, the problem arises that the orientation of the position measurement probe with respect to rotation around an axis which is perpendicular to the lengthwise axis of the cylindrical body and perpendicular to the peripheral surface is not determined very accurately by the geometry of the peripheral surface and the contact surface, i.e., for example, for a horizontal roller, when the position measurement probe is attached to the top of the roller, the angle of elevation of the position measurement probe is determined relatively accurately by mechanical contact, but not the azimuth angle. To increase the accuracy of the azimuth angle of the position measurement probe in this case, the distance between the two attachment edges of the contact surface and/or its length would have to be increased; however, this is essentially limited for reasons of cost and manageability.
Japanese Laid-open patent application S60-158310 discloses an angle measurement method and device for measuring the angle between two planes that form tow mutually separate structures in constructions sites, shipbuilding yards and the like. In the disclosed method and device, angular velocities are sensed by mechanical gyros, and resultant angular velocity signals are integrated to convert them into angles. However, mechanical gyros do not produce a high degree of precision, and there is no disclosure as to if or how the method and device might be applied to cylinders or rolls.
The primary object of this invention is to devise a process for determining the alignment of a cylindrical body with reference to a reference direction, which can be done easily and economically, and yet can still yield results with sufficient accuracy even for bodies with very large diameters.
This object is achieved as in accordance with the invention by a process in which, by means of a position measurement probe which is calibrated with respect to a reference direction, a first position measurement is taken at a first measurement position on a peripheral surface of a cylindrical body, and at least one second measurement is taken at least one second position on the peripheral surface of the body which is displaced from the first measurement position by an angle of rotation in the peripheral direction with respect to the axis of the body, and from the measurements taken, the alignment of the body with respect to the reference direction is calculated. In this approach according to the invention, it is advantageous that, by taking into account at least the second measurement position on the peripheral surface of the body with respect to another axis of rotation, the accuracy of the measurement is easily improved overall.